General Verification Process Approaches

The type of verification process used will vary widely. Savings verification programs are designed with specific metering and verification (M&V) protocols. Protocol selection will depend on several factors, including project complexity, metering complexity, magnitude of costs and savings, level of interactivity with other measures, contractual allocation of risk associated with performance factors not controlled by the contractor, and collateral value of the M&V installation with respect to other uses for the data and metering systems.

The M&V process may, therefore, be based on engineering estimates, adjusted utility cost analysis, facility-wide metering, and/or equipment specific pre- and post-construction metering. More extensive programs add significantly to project costs, but also provide more security in verifying system performance, contractual guarantees, and/or in allowing for ongoing system modifications based on monitored performance data. With the continued advancements in direct digital control (DDC) and communications technology, extensive long-term system metering has become less costly, rendering this comprehensive approach increasingly economical. Three general M&V approaches are: 1) Projects for which the potential to perform and generate savings needs to be verified, but the actual performance (savings) can be stipulated:

This approach involves procedures for verifying that baseline conditions have been properly defined; the equipment and/or systems that were contracted to be installed have been installed; the installed equipment/systems meet and continue to meet the specification of the contract in terms of quantity, quality, and rating and continue to operate and perform in accordance with the specification in the contract and meet and continue to meet all functional tests.

2) Projects for which the potential to perform and generate savings needs to be verified and for which actual performance during the term of the contract needs to be measured:

This approach includes the features of Item 1 above, plus procedures for verifying actual achieved energy (or other resource) savings during the term of the contract based on engineering calculations, with metering and monitoring of one or more variables. This approach may also include the use of statistically valid samples.

3) For projects consistent with Item 2 above, except that verification techniques involve utility whole-facility meter analysis and/or computer simulation calibrated with utility billing data.

Regardless of the approach, the starting point is the establishment of the baseline. Without this, there is the risk that energy and other resource use will not be allocated to the appropriate consumers, or that quantification, and hence savings projections, will be in error. The methods of baseline measurement cover the range from the simple and direct to the complex and derived. With all methods, however, the baseline can be conceptually reduced to the sum product of the following three variables:

1. Load or output (in tons cooling, Btuh heating, lumens lighting, tons of cement produced, lbm of laundry washed, etc.)

2. Efficiency (in kW/ton, Btuh fuel/Btuh heating, watt/lumen, kJh/ton of cement, lbm softener salt/lbm wash, etc.)

3. Time

Under the simplest conditions, where all three of these variables are constant, the baseline consumption can be measured directly. At the same time, the constancy can be confirmed by sampling the resource use over a brief time interval and recording the hours of operation with an hour meter.

On the other extreme, where all three variables are changing, establishing baseline consumption is a much more intensive and expensive process. In this case, it is necessary to determine explicitly the functional relationships between these variables and the independent variables that effect the change. Consequently, the baseline methodology requires a detailed understanding of system performance.

Baselines used for savings verification can be developed in the same manner as those used in savings analyses. This process is described in Chapter 41. One important potential difference from the savings analysis process is that the original system usage need not always be determined. Baseline adjustment can be avoided as long as the post-retrofit load is measured directly and the baseline efficiencies are established. With this approach, the savings can be defined as the product of the measured actual load and the difference in efficiency between the original or base system and the new system. In contrast, if the post-retrofit consumption is monitored as opposed to the load, then it is necessary to determine what part of the consumption reflects changes from the new system and what part is due to changes in the baseline conditions. For this, it is necessary to devise models that calculate consumption as a function of all the independent variables, such as temperature, production, occupancy, etc., and then adjust the baseline for these parametric changes.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

Get My Free Ebook


Post a comment